What is the easiest or best way to remove an eccentric crank without some kind of hydraulic puller? I'm going to try to drive a wedge into the split. And then use a sledge hammer. I suppose it might weigh quite of bit, too.

Greetings:
Eccentric cranks are designed to be removed just as you described. Use a wedge with a gradual taper, the one that I use is about 1/8th inch in 12 inches. I place the wedge on an angle beneath the crank pin being careful not to damage the main rod bearing. After a couple of solid strikes with your sledge you'll be able to jiggle the crank a bit. A couple more strikes and you'll be able to jiggle and pull on the crank towards you and off. You're correct: they are heavy (read: you ought to be wearing steel toe boots). It is good practice to use a paint marker, steel stamp or such (not a chisel!) to identify the crank and other parts "R" or "L" (in North America, the engineer is always on the Right side of the locomotive (unless your locomotive was made overseas, except for Chinese SY-M class).
Good luck!
J.David

But what would preservation organizations be without eccentric cranks?

Even with steel toed boots, you better keep your feet in the clear. 40 years ago, one of the old machinists from CB&Q days told me about the time a couple laborers set a crosshead down on a slightly uneven part of the roundhouse floor right next to him. He was busy BSing and drinking coffee, so he didn't notice it wobbling until it fell on his foot, smashing the steel toe of his boot flat, with his toes inside.

Rule G or no Rule G, they sent somebody out for a fifth of whiskey, and called the company sawbones. It came down to a choice between cutting off the front part of his foot, or cutting his boot off with a torch. He took the second option in hopes of saving his toes, and said he never experienced such pain in his life, in spite of the whiskey used both internally and externally. Needless to say his toes were never the same again.

The moral of the story is: You only got to screw up for a second to change your life forever.

Everybody Take Care & WORK SAFE

Don't neglect to pull the clamp bolt completely out, don't just loosen it. Half of its diameter is in the crankpin, so it locks the ecc. crank onto the crankpin. More than just friction holds it in place.

Damn, you beat me to it.

I was going to say "I thought we already had a thread on curbing your docents.

Thank you for your help.